A drone loaded with methamphetamine crashed in a Mexican parking lot near the California border on Tuesday.

The craft was carrying close to 6 pounds of meth, and officials say it may have crashed because it was overloaded, according to the LA Times. It fell in the parking lot of a supermarket in Zona Rio, near the San Ysidro Port of Entry.

Drones that are used to carry drugs over the border are called “blind mules,” says the Tijuana Public Safety Secretariat. This recent incident is under investigation.